1. Field of the Invention
This invention relates to a simplified water heater for heating water or other beverages using a portable gas heater and, more particularly, to a water heater utilized in obtaining a minimum amount of hot water quickly and easily.
2. Description of the Prior Art
During outdoor activities such as camping, when a small amount of hot water is necessary in cooking a precooked food or for making tea or coffee, a portable gas heater is generally used in heating water in a kettle.
As seen from FIG. 23 of the accompanying drawings, an existing gas burner for use with that type of portable gas heater is provided with a disk-like or circular burner with a plurality of upwardly directed gas outlets (holes for flames) arranged radially.
With a heated vessel such as a kettle and a cup situated upon the heater having the above structure, flames first spread over the bottom surface of the vessel, as designated by arrows in the drawing. Subsequently, the flames rise along the side surface of the vessel to surround, thereby heating the vessel.
Although the water heaters are different in size, bottom shape, and materials, the thermal efficiency of those existing heaters usually reside in the range of; 40%-50% for a gas burner for domestic use, 30%-40% for a large-sized gas burner, and 30%-40% for a heated vessel having a flat bottom. This is mainly due to a dissipation of the heat accumulated in the vessel into the atmosphere through the side surface thereof, provided that the combustion of gas at the gas burner is perfect.
In gas heaters, it is generally expected that the consumption rate of heat energy be as efficient as possible.
Particularly, in the case of a portable gas heater using a cartridge gas cylinder, in view of the characteristics thereof, improvements in the combustion efficiency of gas leads to a gas cylinder having a longer life span with a limited volume of gas, being reduced in size and weight, and being convenient to carry, thereby resulting in wider applications.
However, since the existing portable gas heaters are restricted in the heating power, a drop in the heating power or the escape of heat from the surface of the vessel (i.e., an open-air cooling) is increased with an ambient temperature of 10 centigrade or less, thereby causing a significant reduction in the heating power.
Under such a condition, in order to prevent as little heat loss as possible, it is essential to form a thermal insulating layer, between the heated vessel and the atmosphere, utilizing the spreading flames along the side surface of the vessel, as if surrounding the vessel.
The differences in the size and the shape of vessels renders the burner difficult to design so that the fire spreads as mentioned above, and the design of the burner is further restricted by the requirement for a certain level of heating power.
Even if the burner can be designed to meet such conditions, the aforementioned shield stream formed around the vessel is easily blown away when it is used in the field, thereby causing a drop in the heating efficiency. Such a decrease in the efficiency is especially noteworthy in the case of a compact heater with small heating power.
In order to cope with such a situation, if a heated vessel which is surrounded with an insulating material is used, the application of heat will be limited only to the bottom thereof, again resulting in the ineffective heat exchange of the gas. Moreover, in this instance, the side wall of the vessel may be damaged by the heat of the gas fire.